docs: def cumulative_value(self, slip, mmax, mag_value, bbar, dbar, beta):
          '''
          Returns the rate of events with M > mag_value
  
          :param float slip:
              Slip rate in mm/yr
          :param float mmax:
              Maximum magnitude
          :param float mag_value:
              Magnitude value
          :param float bbar:
              \bar{b} parameter (effectively = b * log(10.))
          :param float dbar:
              \bar{d} parameter
          :param float beta:
              Beta value of formula defined in Eq. 20 of Anderson & Luco (1983)
          '''
          delta_m = (mmax - mag_value)
          a_1 = self._get_a1_value(bbar, dbar, slip / 10., beta, mmax)
          return a_1 * np.exp(bbar * delta_m) * (delta_m > 0.0)